Security through obscurity?

The new notification system will tell you when you've been friended, but not when you've been unfriended.

Which means I'm currently subscribing to an external source which grabs a copy of my friends list, compares it with a cached copy, and tells me if someone unfriends me. (You can subscribe to it here if you really care, or subscribe to your own by looking at the RSS url and replacing my username with yours).

Anyway - this is _hideously_ inefficient. The data goes from the LJ database, out to a third party, and then back again, so I can see information LJ could just supply to me. Why is this, exactly? Some kind of security by obscurity?